Azeotrope-like compositions and their use

ABSTRACT

The invention provides azeotrope-like compositions consisting essentially of R f  OC 2  H 5 , where R f  is a branched or straight chain perfluoroalkyl group having 4 carbon atoms, and an organic solvent selected from the group consisting of: straight chain, branched chain and cyclic alkanes having 6 to 8 carbon atoms; esters having 4 carbon atoms; ketones having 4 carbon atoms; disiloxanes having 6 carbon atoms; cyclic and acyclic ethers having 4 to 6 carbon atoms; chlorinated alkanes having 3 to 4 carbon atoms and chlorinated alkenes having 2 carbon atoms. The compositions are useful for cleaning, as solvents or carriers for coating and as heat transfer materials.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of U.S. patent application Ser. No.08/649,743 filed on May 15, 1996 now U.S. Pat. No. 5,814,595 which was acontinuation-in-part of U.S. patent application Ser. No. 08/442,399filed on May 16, 1995, now abandoned.

FIELD OF THE INVENTION

The invention relates to azeotropes and methods of using azeotropes toclean substrates, deposit coatings and transfer thermal energy.

BACKGROUND

Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) havebeen used in a wide variety of solvent applications such as drying,cleaning (e.g., the removal of flux residues from printed circuitboards), and vapor degreasing. Such materials have also been used inrefrigeration and heat transfer processes. While these materials wereinitially believed to be environmentally benign, they have now beenlinked to ozone depletion. According to the Montreal Protocol and itsattendant amendments, production and use of CFCs must be discontinued(see, e.g., P. S. Zurer, "Looming Ban on Production of CFCs, HalonsSpurs Switch to Substitutes," Chemical & Engineering News, page 12, Nov.15, 1993). The characteristics sought in replacements, in addition tolow ozone depletion potential, typically have included boiling pointranges suitable for a variety of solvent cleaning applications, lowflammability, and low toxicity. Solvent replacements also should havethe ability to dissolve both hydrocarbon-based and fluorocarbon-basedsoils. Preferably, substitutes will also be low in toxicity, have noflash points (as measured by ASTM D3278-89), have acceptable stabilityfor use in cleaning applications, and have short atmospheric lifetimesand low global warming potentials.

Certain perfluorinated (PFCs) and highly fluorinated hydrofluorocarbon(HFCs) materials have also been evaluated as CFC and HCFC replacementsin solvent applications. While these compounds are generallysufficiently chemically stable, nontoxic and nonflammable to be used insolvent applications, PFCs tend to persist in the atmosphere, and PFCsand HFCs are generally less effective than CFCs and HCFCs for dissolvingor dispersing hydrocarbon materials. Also, mixtures of PFCs or HFCs withhydrocarbons tend to be better solvents and dispersants for hydrocarbonsthan PFCs or HFCs alone.

Many azeotropes possess properties that make them useful solvents. Forexample, azeotropes have a constant boiling point, which avoids boilingtemperature drift during processing and use. In addition, when a volumeof an azeotrope is used as a solvent, the properties of the solventremain constant because the composition of the solvent does not change.Azeotropes that are used as solvents also can be recovered convenientlyby distillation.

There currently is a need for azeotrope or azeotrope-like compositionsthat can replace CFC- and HCFC-containing solvents. Preferably thesecompositions would be non-flammable, have good solvent power, cause nodamage to the ozone layer and have a relatively short atmosphericlifetime so that they do not significantly contribute to global warming.

SUMMARY

In one aspect, the invention provides azeotrope-like compositionsconsisting essentially of a hydrofluorocarbon ether and organic solvent.The hydrofluorocarbon ether is represented by the general formula R_(f)OC₂ H₅, where R_(f) is a branched or straight chain perfluoroalkyl grouphaving 4 carbon atoms and the organic solvent is selected from the groupconsisting of: straight chain, branched chain and cyclic alkanescontaining 6 to 8 carbon atoms, esters containing 4 carbon atoms,ketones containing 4 carbon atoms, siloxanes containing 6 carbon atoms,cyclic and acyclic ethers containing 4 to 6 carbon atoms, chlorinatedalkanes containing 3 to 4 carbon atoms, chlorinated alkenes having 2 to3 carbon atoms, alcohols containing one to four carbon atoms,fluorinated alcohols having 3 carbon atoms, 1-bromopropane andacetonitrile. While the concentrations of the hydrofluorocarbon etherand organic solvent included in an azeotrope-like composition may varysomewhat from the concentrations found in the azeotrope formed betweenthem and remain a composition within the scope of this invention, theboiling points of the azeotrope-like compositions will be substantiallythe same as those of their corresponding azeotropes. Preferably, theazeotrope-like compositions boil at ambient pressure at temperaturesthat are within about 1° C. of the temperatures at which theircorresponding azeotropes boil at the same pressure.

In another aspect, the invention provides a method of cleaning objectsby contacting the object to be cleaned with one or more of theazeotrope-like compositions of this invention or the vapor of suchcompositions until undesirable contaminants or soils on the object aredissolved, dispersed or displaced and rinsed away.

In yet another aspect, the invention also provides a method of coatingsubstrates using the azeotrope-like compositions as solvents or carriersfor the coating material. The process comprises the step of applying toat least a portion of at least one surface of a substrate a liquidcoating composition comprising: (a) an azeotrope-like composition, and(b) at least one coating material which is soluble or dispersible in theazeotrope-like composition. Preferably, the process further comprisesthe step of removing the azeotrope-like composition from the liquidcoating composition, for example, by evaporation.

The invention also provides coating compositions comprising anazeotrope-like composition and coating material which are useful in theaforementioned coating process.

In yet another aspect, the invention provides a method of transferringthermal energy using the azeotrope-like compositions as heat transferfluids.

DETAILED DESCRIPTION

The azeotrope-like compositions are mixtures of hydrofluorocarbon etherand organic solvent which, if fractionally distilled, produce adistillate fraction that is an azeotrope of the hydrofluorocarbon etherand organic solvent.

The azeotrope-like compositions boil at temperatures that areessentially the same as the boiling points of their correspondingazeotropes. Preferably, the boiling point of an azeotrope-likecomposition at ambient pressure is within about 1° C. of the boilingpoint of its azeotrope measured at the same pressure. More preferably,the azeotrope-like compositions will boil at temperatures that arewithin about 0.5° C. of the boiling points of their correspondingazeotropes measured at the same pressure.

The concentrations of the hydrofluorocarbon ether and organic solvent ina particular azeotrope-like composition may vary substantially from theamounts contained in the composition's corresponding azeotrope, and themagnitude of such permissible variation depends upon the organic solventused to make the composition. Preferably, the concentrations ofhydrofluorocarbon ether and organic solvent in an azeotrope-likecomposition vary no more than about ten percent from the concentrationsof such components contained in the azeotrope formed between them atambient pressure. More preferably, the concentrations are within aboutfive percent of those contained in the azeotrope. Most preferably, theazeotropic composition contains essentially the same concentrations ofthe ether and solvent as are contained in the azeotrope formed betweenthem at ambient pressure. Where the concentrations of ether and organicsolvent in an azeotrope-like composition differ from the concentrationscontained in the corresponding azeotrope, the preferred compositionscontain a concentration of the ether that is in excess of the ether'sconcentration in the azeotrope. Such compositions are likely to be lessflammable than azeotrope-like compositions in which the organic solventis present in a concentration that is in excess of its concentration inthe azeotrope. The most preferred compositions will exhibit nosignificant change in the solvent power of the composition over time.

The azeotrope-like compositions of this invention may also contain, inaddition to the hydrofluorocarbon ether and organic solvent, smallamounts of other compounds which do not interfere in the formation ofthe azeotrope. For example, small amounts of surfactants may be presentin the azeotrope-like compositions of the invention to improve thedispersibility or solubility of materials, such as water, soils orcoating materials (e.g., perfluoropolyether lubricants andfluoropolymers), in the azeotrope-like composition. Azeotropes orazeotrope-like compositions containing as a component1,2-trans-dichloroethylene preferably also contain about 0.25 to 1weight percent of nitromethane and about 0.05 to 0.4 weight percent ofepoxy butane to prevent degradation of the 1,2-trans-dichloroethylene.Most preferably, such compositions will contain about 0.5 weight percentnitromethane and 0.1 weight percent of the epoxy butane.

The characteristics of azeotropes are discussed in detail in Merchant,U.S. Pat. No. 5,064,560 (see, in particular, col. 4, lines 748).

The hydrofluorocarbon ether useful in the invention can be representedby the following general formula:

    R.sub.f --O--C.sub.2 H.sub.5                               (I)

where, in the above formula, R_(f) is selected from the group consistingof linear or branched perfluoroalkyl groups having 4 carbon atoms. Theether may be a mixture of ethers having linear or branchedperfluoroalkyl R_(f) groups. For example, perfluorobutyl ethyl ethercontaining about 95 perfluro-n-butyl ethyl ether and 5 weight percentperfluoroisobutyl ethyl ether and perfluorobutyl ethyl ether containingabout 15 to 35 weight percent perfluoroisobutyl ethyl ether and 85 to 65weight percent perfluoro-n-butyl ethyl ether are also useful in thisinvention.

The hydrofluorocarbon ether can be prepared by alkylation of: CF₃ CF₂CF₂ CF₂ O⁻⁻, CF₃ CF(CF₃)CF₂ O⁻⁻, C₂ F₅ C(CF₃)FO⁻⁻, C(CF₃)₃ O⁻⁻ andmixtures thereof The aforementioned perfluoroalkoxides can be preparedby reaction of: CF₃ CF₂ CF₂ C(O)F, CF₃ CF(CF₃)C(O)F and C₂ F₅ C(O)CF₃,and mixtures thereof with any suitable source of anhydrous fluoride ionsuch as anhydrous alkali metal fluoride (e.g., potassium fluoride orcesium fluoride) or anhydrous silver fluoride in an anhydrous polar,aprotic solvent in the presence of a quaternary ammonium compound suchas "ADOGEN 464" available from the Aldrich Chemical Company. Theperfluoroalkoxide, C(CF₃)₃ O⁻⁻, can be prepared by reacting C(CF₃)₃ OHwith a base such as KOH in an anhydrous polar, aprotic solvent in thepresence of a quaternary ammonium compound. General preparative methodsfor the ethers are also described in French Patent No. 2,287,432 andGerman Patent No. 1,294,949.

Suitable alkylating agents for use in the preparation include dialkylsulfates (e.g., diethyl sulfate), alkyl halides (e.g., ethyl iodide),alkyl p-toluenesulfonates (e.g., ethyl p-toluenesulfonate), alkylperfluoroalkanesulfonates (e.g., ethyl perfluoromethanesulfonate), andthe like. Suitable polar, aprotic solvents include acyclic ethers suchas diethyl ether, ethylene glycol dimethyl ether, and diethylene glycoldimethyl ether, carboxylic acid esters such as methyl formate, ethylformate, methyl acetate, diethyl carbonate, propylene carbonate, andethylene carbonate; alkyl nitriles such as acetonitrile; alkyl amidessuch as N,N-dimethylformamide, N,N-diethylformamide, andN-methylpyrrolidone; alkyl sulfoxides such as dimethyl sulfoxide; alkylsulfones such as dimethylsulfone, tetramethylene sulfone, and othersulfolanes; oxazolidones such as N-methyl-2-oxazolidone; and mixturesthereof

Perfluorinated acyl fluorides (for use in preparing thehydrofluorocarbon ether) can be prepared by electrochemical fluorination(ECF) of the corresponding hydrocarbon carboxylic acid (or a derivativethereof), using either anhydrous hydrogen fluoride (Simons ECF) orKF.2HF (Phillips ECF) as the electrolyte. Perfluorinated acyl fluoridesand perfluorinated ketones can also be prepared by dissociation ofperfluorinated carboxylic acid esters (which can be prepared from thecorresponding hydrocarbon or partially-fluorinated carboxylic acidesters by direct fluorination with fluorine gas). Dissociation can beachieved by contacting the perfluorinated ester with a source offluoride ion under reacting conditions (see the methods described inU.S. Pat. No. 3,900,372 (Childs) and U.S. Pat. No. 5,466,877 (Moore)),or by combining the ester with at least one initiating reagent selectedfrom the group consisting of gaseous, non-hydroxylic nucleophiles;liquid, non-hydroxylic nucleophiles; and mixtures of at least onenon-hydroxylic nucleophile (gaseous, liquid, or solid) and at least onesolvent which is inert to acylating agents.

Initiating reagents which can be employed in the dissociation are thosegaseous or liquid, non-hydroxylic nucleophiles and mixtures of gaseous,liquid, or solid, non-hydroxylic nucleophile(s) and solvent (hereinaftertermed "solvent mixtures") which are capable of nucleophilic reactionwith perfluorinated esters. The presence of small amounts of hydroxylicnucleophiles can be tolerated. Suitable gaseous or liquid,non-hydroxylic nucleophiles include dialkylamines, trialkylamines,carboxamides, alkyl sulfoxides, amine oxides, oxazolidones, pyridines,and the like, and mixtures thereof. Suitable non-hydroxylic nucleophilesfor use in solvent mixtures include such gaseous or liquid,non-hydroxylic nucleophiles, as well as solid, non-hydroxylicnucleophiles, e.g., fluoride, cyanide, cyanate, iodide, chloride,bromide, acetate, mercaptide, alkoxide, thiocyanate, azide,trimethylsilyl difluoride, bisulfite, and bifluoride anions, which canbe utilized in the form of alkali metal, ammonium, alkyl-substitutedammonium (mono-, di-, tri-, or tetra-substituted), or quaternaryphosphonium salts, and mixtures thereof Such salts are in generalcommercially available but, if desired, can be prepared by knownmethods, e.g., those described by M. C. Sneed and R. C. Brasted inComprehensive Inorganic Chemistry, Volume Six (The Alkali Metals), pages61-64, D. Van Nostrand Company, Inc., New York (1957), and by H. Kobleret al. in Justus Liebigs Ann. Chem., 1978, 1937.1,4-diazabicyclo[2.2.2]octane and the like are also suitable solidnucleophiles.

The hydrofluorocarbon ethers used to prepare the azeotrope-likecompositions of this invention do not deplete the ozone in the earth'satmosphere and have surprisingly short atmospheric lifetimes therebyminimizing their impact on global warming. Reported in Table 1, is anatmospheric lifetime for the hydrofluorocarbon ether which wascalculated using the technique described in Y. Tang, Atmospheric Fate ofVarious Fluorocarbons, M. S. Thesis, Massachusetts Institute ofTechnology (1993). The results of this calculation are presented inTable 1 under the heading "Atmospheric Lifetime (years)". Theatmospheric lifetimes of the hydrofluorocarbon ether and itscorresponding hydrofluorocarbon alkane were also calculated using acorrelation developed between the highest occupied molecular orbitalenergy and the known atmospheric lifetimes of hydrofluorocarbons andhydrofluorocarbon ethers that is similar to a correlation described byCooper et al. in Atmos. Environ. 26A, 7, 1331 (1992). These values arereported in Table 1 under the heading "Estimated Atmospheric Lifetime."The global warming potential of the hydrofluorocarbon ether wascalculated using the equation described in the Intergovernmental Panel'sClimate Change: The IPCC Scientific Assessment, Cambridge UniversityPress (1990). The results of the calculation are presented in Table 1under the heading "Global Warming Potential". It is apparent from thedata in Table 1 that the hydrofluorocarbon ether has a relatively shortestimated atmospheric lifetime and a relatively small global warmingpotential. Surprisingly, the hydrofluorocarbon ether also has asignificantly shorter estimated atmospheric lifetime than itscorresponding hydrofluorocarbon alkane.

                  TABLE 1                                                         ______________________________________                                                  Estimated                                                              Atmospheric Atmospheric Global Warming                                        Lifetime Lifetime Potential                                                  Compound (years) (years) (100 year ITH)                                     ______________________________________                                        C.sub.4 F.sub.9 --C.sub.2 H.sub.5                                                       2.0         --        --                                              C.sub.4 F.sub.9 --O--C.sub.2 H.sub.5 0.5 1.2 70                             ______________________________________                                    

Typical organic solvents useful in this invention include straightchain, branched chain and cyclic alkanes containing 6 to 8 carbon atoms(e.g., hexane, heptane, cyclohexane, methylcyclohexane, heptane andisooctane); esters containing 4 carbon atoms (e.g., methyl propionateand ethyl acetate); ketones containing 4 carbon atoms (e.g., methylethyl ketone); siloxanes containing 6 carbon atoms (e.g.,hexamethyldisiloxane); cyclic and acyclic ethers containing 4 to 6carbon atoms (e.g., t-amyl methyl ether, 1,4-dioxane, tetrahydrofuran,tetrahydropyran and 1,2-dimethoxyethane); chlorinated alkanes containing3 to 4 carbon atoms (e.g., 1,2-dichloropropane, 2,2-dichloropropane and1-chlorobutane); chlorinated alkenes having 2 to 3 carbon atoms (e.g.,trans-1,2-dichloroethylene and 2,3-dichloro-1-propene); alcoholscontaining one to four carbon atoms (e.g., methanol, ethanol,2-propanol, 1-propanol and t-butanol); fluorinated alcohols having 3carbon atoms (e.g., pentafluoro-1-propanol and hexafluoro-2-propanol);1-bromopropane; and acetonitrile.

Preferably, the azeotrope-like compositions are homogeneous. That is,they form a single phase under ambient conditions, i.e., at roomtemperature and atmospheric pressure.

The azeotrope-like compositions are prepared by mixing the desiredamounts of hydrofluorocarbon ether, organic solvent and any other minorcomponents such as surfactants together using conventional mixing means.

The cleaning process of the invention can be carried out by contacting acontaminated substrate with one of the azeotrope-like compositions ofthis invention until the contaminants on the substrate are dissolved,dispersed or displaced in or by the azeotrope-like composition and thenremoving (for example by rinsing the substrate with fresh,uncontaminated azeotrope-like composition or by removing a substrateimmersed in an azeotrope-like composition from the bath and permittingthe contaminated azeotrope-like composition to flow off of thesubstrate) the azeotrope-like composition containing the dissolved,dispersed or displaced contaminant from the substrate. Theazeotrope-like composition can be used in either the vapor or the liquidstate (or both), and any of the known techniques for "contacting" asubstrate can be utilized. For example, the liquid azeotrope-likecomposition can be sprayed or brushed onto the substrate, the vaporousazeotrope-like composition can be blown across the substrate, or thesubstrate can be immersed in either a vaporous or a liquidazeotrope-like composition. Elevated temperatures, ultrasonic energy,and/or agitation can be used to facilitate the cleaning. Variousdifferent solvent cleaning techniques are described by B. N. Ellis inCleaning and Contamination of Electronics Components and Assemblies,Electrochemical Publications Limited, Ayr, Scotland, pages 182-94(1986).

Both organic and inorganic substrates can be cleaned by the process ofthe invention. Representative examples of the substrates include metals;ceramics; glass; polymers such as: polycarbonate, polystyrene andacrylonitrile-butadiene-styrene copolymer; natural fibers (and fabricsderived therefrom) such as: cotton, silk, linen, wool, ramie; fur;leather and suede; synthetic fibers (and fabrics derived therefrom) suchas: polyester, rayon, acrylics, nylon, polyolefin, acetates, triacetatesand blends thereof, fabrics comprising a blend of natural and syntheticfibers; and composites of the foregoing materials. The process isespecially useful in the precision cleaning of electronic components(e.g., circuit boards), optical or magnetic media, and medical devicesand medical articles such as syringes, surgical equipment, implantabledevices and prosthesis.

The cleaning process of the invention can be used to dissolve or removemost contaminants from the surface of a substrate. For example,materials such as light hydrocarbon contaminants; higher molecularweight hydrocarbon contaminants such as mineral oils, greases, cuttingand stamping oils and waxes; fluorocarbon contaminants such asperfluoropolyethers, bromotrifluoroethylene oligomers (gyroscopefluids), and chlorotrifluoroethylene oligomers (hydraulic fluids,lubricants); silicone oils and greases; solder fluxes; particulates; andother contaminants encountered in precision, electronic, metal, andmedical device cleaning can be removed. The process is particularlyuseful for the removal of hydrocarbon contaminants (especially, lighthydrocarbon oils), fluorocarbon contaminants, particulates, and water(as described in the next paragraph).

To displace or remove water from substrate surfaces, the cleaningprocess of the invention can be carried out as described in U.S. Pat.No. 5,125,978 (Flynn et al.) by contacting the surface of an articlewith an azeotrope-like composition which preferably contains a non-ionicfluoroaliphatic surface active agent. The wet article is immersed in theliquid azeotrope-like composition and agitated therein, the displacedwater is separated from the azeotrope-like composition, and theresulting water-free article is removed from the liquid azeotrope-likecomposition. Further description of the process and the articles whichcan be treated are found in U.S. Pat. No. 5,125,978 and the process canalso be carried out as described in U.S. Pat. No. 3,903,012 (Brandreth).

The azeotrope-like compositions can also be used in coating depositionapplications, where the azeotrope-like composition functions as acarrier for a coating material to enable deposition of the material onthe surface of a substrate. The invention thus also provides a coatingcomposition comprising the azeotrope-like composition and a process fordepositing a coating on a substrate surface using the azeotrope-likecomposition. The process comprises the step of applying to at least aportion of at least one surface of a substrate a coating of a liquidcoating composition comprising (a) an azeotrope-like composition, and(b) at least one coating material which is soluble or dispersible in theazeotrope-like composition. The coating composition can further compriseone or more additives (e.g., surfactants, coloring agents, stabilizers,anti-oxidants, flame retardants, and the like). Preferably, the processfurther comprises the step of removing the azeotrope-like compositionfrom the deposited coating by, e.g., allowing evaporation (which can beaided by the application of, e.g., heat or vacuum).

The coating materials which can be deposited by the process includepigments, lubricants, stabilizers, adhesives, anti-oxidants, dyes,polymers, pharmaceuticals, release agents, inorganic oxides, and thelike, and combinations thereof Preferred materials includeperfluoropolyether, hydrocarbon, and silicone lubricants; amorphouscopolymers of tetrafluoroethylene; polytetrafluoroethylene; andcombinations thereof Representative examples of materials suitable foruse in the process include titanium dioxide, iron oxides, magnesiumoxide, perfluoropolyethers, polysiloxanes, stearic acid, acrylicadhesives, polytetrafluoroethylene, amorphous copolymers oftetrafluoroethylene, and combinations thereof Any of the substratesdescribed above (for cleaning applications) can be coated via theprocess of the invention. The process can be particularly useful forcoating magnetic hard disks or electrical connectors withperfluoropolyether lubricants or medical devices with siliconelubricants.

To form a coating composition, the components of the composition (i.e.,the azeotrope-like composition, the coating material(s), and anyadditive(s) utilized) can be combined by any conventional mixingtechnique used for dissolving, dispersing, or emulsifying coatingmaterials, e.g., by mechanical agitation, ultrasonic agitation, manualagitation, and the like. The azeotrope-like composition and the coatingmaterial(s) can be combined in any ratio depending upon the desiredthickness of the coating, but the coating material(s) preferablyconstitute from about 0.1 to about 10 weight percent of the coatingcomposition for most coating applications.

The deposition process of the invention can be carried out by applyingthe coating composition to a substrate by any conventional technique.For example, the composition can be brushed or sprayed (e.g., as anaerosol) onto the substrate, or the substrate can be spin-coated.Preferably, the substrate is coated by immersion in the composition.Immersion can be carried out at any suitable temperature and can bemaintained for any convenient length of time. If the substrate is atubing, such as a catheter, and it is desired to ensure that thecomposition coats the lumen wall, it may be advantageous to draw thecomposition into the lumen by the application of reduced pressure.

After a coating is applied to a substrate, the azeotrope-likecomposition can be removed from the deposited coating by evaporation. Ifdesired, the rate of evaporation can be accelerated by application ofreduced pressure or mild heat. The coating can be of any convenientthickness, and, in practice, the thickness will be determined by suchfactors as the viscosity of the coating material, the temperature atwhich the coating is applied, and the rate of withdrawal (if immersionis utilized).

Objects and advantages of this invention are further illustrated by thefollowing examples, but the particular materials and amounts thereofrecited in these examples, as well as other conditions and details,should not be construed to unduly limit this invention.

EXAMPLES Examples 1-2

The preparation and identification of the azeotrope-like compositions ofthis invention are described in the following Examples.

Preparation of Ether "A". Ether "A", used to prepare the azeotrope-likecompositions and azeotropes of the following Examples was prepared asfollows.

A 20 gallon Hastalloy C reactor, equipped with a stirrer and a coolingsystem, was charged with spray-dried potassium fluoride (7.0 kg, 120.3mole). The reactor was sealed, and the pressure inside the reactor wasreduced to less than 100 torr. Anhydrous dimethyl formamide (22.5 kg)was then added to the reactor, and the reactor was cooled to below 0° C.with constant agitation. Heptafluorobutyryl fluoride (22.5 kg of 58%purity, 60.6 mole) was added to the reactor contents. When thetemperature of the reactor reached -20° C., diethyl sulfate (18.6 kg,120.8 mole) was added to the reactor over a period of approximately twohours. The resulting mixture was then held for 16 hours with continuedagitation, was raised to 50° C. for an additional four hours tofacilitate complete reaction, and was cooled to 20° C. Then, volatilematerial (primarily perfluorooxacyclopentane present in the startingheptafluorobutyryl fluoride) was vented from the reactor over athree-hour period. The reactor was then resealed, and water (6.0 kg) wasadded slowly to the reactor. After the exothermic reaction of the waterwith unreacted perfluorobutyryl fluoride subsided, the reactor wascooled to 25° C., and the reactor contents were stirred for 30 minutes.The reactor pressure was carefully vented, and the lower organic phaseof the resulting product was removed to afford 17.3 kg of material whichwas 73% C₄ F₉ OC₂ H₅. Analysis revealed the product to be approximately95 wt.% perfluoro-n-butyl ethyl ether and 5 wt. % perfluoro-isobutylethyl ether. The product identity was confirmed by GCMS and by ¹ H, ¹⁹ FNMR and IR and boiled at 76.2° C. at 739.6 torr.

Preparation of Ether "B". Into a 100 gallon Hastalloy C reactor with astirrer and a cooling system was charged 21.8 kg (375.2 mole) ofspray-dried potassium fluoride. The reactor was sealed and the pressureinside the reactor was reduced to less than 100 torr. Anhydrous diglyme(139.4 kg), triethylamine (5.44 kg, 53.9 mole), ADOGEN 464™ (1.54 kg,3.33mole), diethyl sulfate (62.6 kg, 406 mole) were added to the reactorfollowed by perfluoroisobutyryl fluoride (86.3 kg of 80% acid fluoridecontent, 319.6 mole). The resulting mixture was then held at 60° C. for18 hours with continued agitation, raised to 85° C., then water (20 kg)and 45% aqueous potassium hydroxide (25.4 kg, 203.9 mole) was added tothe reaction mixture. After stirring for approximately 30 minutes, thereactor was cooled to 43° C. and an additional 136.2 kg of water wasadded, followed by 48% aqueous hydrogen fluoride (4.08 kg, 98.1 mole) toobtain a final pH of 7 to 8. The product was separated from the reactionmixture by distillation to obtain 74.0 kg of crude product which wasfurther purified by a second distillation. The process provided aproduct that was approximately 82 wt. % perfluoro-isobutyl ethyl etherand 18 wt. % perfluoro-n-butyl ethyl ether, which boiled at about 75.0°C. at 739.3 torr. The product identity was confirmed by CGMS, ¹ H and ¹⁹FNMR and IR.

Examples 3-30

Preparation and Identification of Azeotrope Compositions: EbulliometerMethod.

The azeotropes of this invention were initially identified by screeningmixtures of hydrofluorocarbon ether and various organic solvents usingan ebulliometer or boiling point apparatus (specifically a Model MBP-100available from Cal-Glass for Research, Inc., Costa Mesa California). Thelower boiling component of the test mixtures (typically an amount of 25to 30 mLs) was added to the boiling point apparatus, heated and allowedto equilibrate to its boiling point (typically about 30 minutes). Afterequilibration, the boiling point was recorded, a 1.0 mL aliquot of thehigher boiling component was added to the apparatus and the resultingmixture was allowed to equilibrate for about 30 minutes at which timethe boiling point was recorded. The test continued basically asdescribed above, with additions to the test mixture of 1.0 mL of thehigher boiling point component every 30 minutes until 15 to 20 mLs ofthe higher boiling point component had been added. The presence of anazeotrope was noted when the test mixture exhibited a lower boilingpoint than the boiling point of the lowest boiling component of the testmixture. The compositions corresponding to the aforementioned boilingpoints were determined. The composition (volume %) of the organicsolvent in the composition was then plotted as a function of boilingpoint. The azeotrope-like compositions boiling at temperatures withinabout 1° C. of the respective azeotrope boiling point were thenidentified from the plot and this compositional data (on a weight %basis) as well as the boiling point range corresponding to thecompositions (expressed as the difference between the compositionboiling point and the azeotrope boiling point) are presented in Table 2.

The organic solvents used to prepare the azeotrope-like compositionsdescribed in these Examples were purchased commercially from the AldrichChemical and Fluka Chemical Companies.

                                      TABLE 2                                     __________________________________________________________________________                                 Boiling                                              Conc. Solvent Conc. Ether Temp. Range Pressure                              Ex. Organic Solvent:Ether (wt %) (wt %) (                                                                       ° C.) (torr)                       __________________________________________________________________________     3 Hexane:Ether A                                                                             27.8-75.5                                                                            82.2-24.5                                                                           61.8   723                                          4 Heptane:Ether A 2.5-21.9 97.5-78.1 73.3 711.4                               5 Isooctane:Ether A 1.5-17.2 98.5-82.8 74.9 732.6                             6 Cyclohexane:Ether A 12.0-47.1  88.0-52.9 66.7 730.5                         7 Methylcyclohexane:Ether A 2.2-26.4 97.8-73.6 73.3 733.2                     8 t-Amyl methyl ether:Ether A 2.2-35.0 97.8-65.0 74.5 736.6                   9 Tetrahydrofuran:Ether A 26.7-80.6  73.3-19.4 61.4 734.2                    10 Tetrahyropyran:Ether A 2.5-30.9  97.5-69.18 73.8 731.9                     11 1,4-Dioxane:Ether A 1.5-17.8 98.5-82.2 74.7 735.7                          12 1,2-Dimethoxyethane:Ether A 4.4-42.5 95.6-57.5 73.7 733.1                  13 Ethyl Acetate:Ether A 11.4-66.7 88.6-33.3 71.0 740.1                       14 Methyl Propionate:Ether A 11.6-62.3  88.4-37.8 71.3 737.4                  15 Methyl Ethyl Ketone:Ether A 9.0-34.2 91.0-65.8 71.0 729.6                  16 Methanol:Ether A 6.4-64.9 93.6-35.1 52.6 720.5                             17 Ethanol:Ether A 5.7-45.2 94.3-54.8 61.7 722.2                              18 2-Propanol:Ether A 6.3-19.8 93.7-80.2 63.7 729.2                           19 1-Propanol:Ether A 4.7-30.6 95.3-69.4 69.8 732.6                           20 t-Butanol:Ether A 7.0-38.9 93.0-61.1 67.3 735.6                            21 Pentafluoro-1-Propanol:Ether 15.7-54.3  84.3-45.7 67.9 735.2                                                   A                                         22 Hexafluoro-2-Propanol:Ether 62.6-98.2  37.4-1.8  56.6 735.7                 A                                                                            23 Hexamethyl Disiloxane:Ether 2.2-15.8 97.8-84.2 75.1 738.1                   A                                                                            24 1-Chlorobutane:Ether A 11.3-61.5  88.7-38.5 69.1 735.7                     25 1,2-Dichloropropane:Ether A 6.4-29.4 93.6-70.6 73.8 737.6                  26 2,2-Dichloropropane:Ether A 23.6-60.0*  76.4-40.0* 66.4 730.8                                                 27 trans-1,2- 53.9-95.5  46.1-4.5                                            43.8 728.7                                   Dichloroethylene:Ether A                                                     28 2,3-Dichloro-1-Propene:Ether 5.1-32.1 94.9-67.9 72.8 735.2                  A                                                                            29 1-Bromopropane:Ether A 22.0-79.1  78.0-20.9 63.2 725                       30 Acetonitrile:Ether A 6.4-55.0 93.6-45.0 65.4 739                         __________________________________________________________________________     *Estimated value based upon symmetrical Boiling Point Curve.             

Examples 31-72

Preparation and Characterization of the Azeotrope-like Compositions bythe Distillation Method.

Mixtures of hydrofluorocarbon ether and organic solvents which exhibiteda boiling point depression in the Ebulliometer Method were evaluatedagain to more precisely determine the composition of the azeotrope.Mixtures of the hydrofluorocarbon and the organic solvent of interestwere prepared and distilled in a concentric tube distillation column(Model 9333 from Ace Glass, Vineland N.J.). The distillation was allowedto equilibrate at total reflux for at least 60 minutes. In eachdistillation, six successive distillate samples, each approximately 5percent by volume of the total liquid charge, were taken while operatingthe column at a liquid reflux ratio of 20 to 1. The composition of thedistillate samples were then analyzed using an HP-5890 Series II PlusGas Chromatograph with a 30 m HP-5 (cross-linked 5% phenyl methylsilicone gum stationary phase, available from Hewlett Packard Co.),NUKOL (available from Supelco Inc.), or STABILWAX DA (available fromAltech Associates) capillary column and a flame ionization detector. Theboiling points of the distillate were measured using a thermocouplewhich was accurate to about 1° C. The compositional data, boiling pointsand ambient pressures at which the boiling points were measured arereported in Table 3.

The azeotropes were also tested for flammability by placing a smallaliquot of the azeotrope in an open aluminum dish and holding a flamesource in contact with the vapor of the azeotrope above the dish. Flamepropagation across the vapor indicated that the azeotrope was flammable.The flammability data is presented in Table 3 under the heading"Flammability".

                                      TABLE 3                                     __________________________________________________________________________                   Ether Conc.                                                                         Organic Solvent                                                                       Boiling Point                                                                       Ambient Pressure                             Example Organic Solvent:Ether (wt %) Conc. (wt %) (                                                                    ° C.) (torr) Flammable      __________________________________________________________________________    31   Hexane:Ether A                                                                          59.7  40.3    61.5  734.1   Yes                                  32 Heptane:Ether A 92.5 7.5 73.2 737.7 Yes                                    33 Heptane:Ether B 89.7 10.3 72.8 737.7 Yes                                   34 Isooctane:Ether A 91.0 9.0 74.0 735.2 Yes                                  35 Isooctane:Ether B 90.9 9.1 73.9 738.4 Yes                                  36 Cyclohexane:Ether A 66.5 33.5 65.8 727.7 Yes                               37 Cyclohexane:Ether B 74.5 25.5 65.7 731.1 Yes                               38 Methylcyclohexane: 88.6 11.4 73.3 737.7 Yes                                 Ether A                                                                      39 Methylcyclohexane: 90.6 9.4 73.0 739.1 Yes                                  Ether B                                                                      40 t-Amyl methyl 85.4 14.6 73.7 737.7 Yes                                      Ether:Ether A                                                                41 t-Amylmethyl 85.2 14.8 72.9 729.4 Yes                                       Ether:Ether B                                                                42 Tetrahydrofuran: 55.4 44.6 62.3 741.0 Yes                                   Ether A                                                                      43 Tetrahydrofuran: 52.6 47.4 61.6 727.3 Yes                                   Ether B                                                                      44 Tetrahydropyran: 83.3 16.7 76.7 742.1 Yes                                   Ether A                                                                      45 1,4-Dioxane:Ether A 91.8 8.2 76.0 740.9 Yes                                46 1,2-Dimethoxyethane: 82.2 17.8 73.0 736.6 Yes                               Ether A                                                                      47 1,2-Dimethoxyethane: 81.9 18.1 73.2 740.9 Yes                               Ether B                                                                      48 Ethyl Acetate:Ether A 68.2 31.8 69.8 736.5 Yes                             49 Ethyl Acetate:Ether B 69.3 30.7 69.7 729.4 Yes                             50 Methyl 73.0 27.0 70.8 736.6 Yes                                             Propionate:Ether A                                                           51 Methyl Ethyl 86.2 13.8 70.2 734.0 Yes                                       Ketone:Ether A                                                               52 Methyl Ethyl 78.9 21.1 70.0 733.3 Yes                                       Ketone:Ether B                                                               53 Methanol:Ether B 84.5 15.5 52.3 733.2 Yes                                  54 Ethanol:Ether B 88.0 12.0 61.3 734.1 Yes                                   55 2-Propanol:Ether B 87.1 12.9 64.9 734.5 Yes                                56 t-Butanol:Ether B 83.7 16.3 67.3 744.2 Yes                                 57 Pentafluoro-1- 75.3 24.7 66.6 730.5 Yes                                     Propanol:Ether B                                                             58 Hexafluoro-2- 34.7 65.3 56.0 731.2 No                                       Propanol:Ether B                                                             59 Hexamethyl 90.6 9.4 74.2 734.0 Yes                                          Disiloxane:Ether A                                                           60 Hexamethyl 89.6 10.4 74.0 743.8 Yes                                         Disiloxane:Ether B                                                           61 1-Chlorobutane: 74.2 25.8 67.9 730.1 Yes                                    Ether A                                                                      62 1-Chlorobutane: 71.9 28.1 67.7 727.3 Yes                                    Ether B                                                                      63 1,2-Dichloropropane: 83.6 16.4 73.0 740.3 No                                Ether A                                                                      64 1,2-Dichloropropane: 86.8 13.2 72.9 745.8 No                                Ether B                                                                      65 2,2-Dichloropropane: 54.9 45.1 67.1 738.7 Yes                               Ether A                                                                      66 2,2-Dichloropropane: 67.7 38.3 65.6 743.8 Yes                               Ether B                                                                      67 trans-1,2- 37.3 62.7 44.5 740.6 No                                          Dichloroethylene                                                              Ether A                                                                      68 trans-1,2- 31.2 68.8 44.8 737.5 No                                          Dichloroethylene:                                                             Ether B                                                                      69 2,3-Dichloro-1- 81.6 18.4 72.8 739.1 Yes                                    Propene:Ether A                                                              70 1-Bromopropane: 55.0 44.0 62.1 733.5 Yes                                    Ether B                                                                      71 Acetonitrile:Ether A 83.0 17.0 65.2 736.2 Yes                              72 Acetonitrile:Ether B 85.4 14.6 63.9 733.7 Yes                            __________________________________________________________________________

Examples 73-114

A number of the azeotrope-like compositions were tested for theirability to dissolve hydrocarbons of increasing molecular weightaccording to the procedure described in U.S. Pat. No. 5,275,669 (Van DerPuy et al.), the description of which is incorporated herein byreference. The data shown in Table 4 was obtained by determining thelargest normal hydrocarbon alkane which was soluble in a particularazeotrope-like composition at a level of 50 volume percent. Thehydrocarbon solubilities in the azeotrope-like compositions weremeasured at both room temperature and the boiling points of theazeotrope-like compositions. The data is reported in Table 4. Thenumbers in Table 4 under the headings "Hydrocarbon @ RT" and"Hydrocarbon @ BP" correspond to the number of carbon atoms in thelargest hydrocarbon n-alkane that was soluble in each of theazeotrope-like compositions at room temperature and the boiling point ofthe azeotrope-like composition, respectively.

The data in Table 4 shows that hydrocarbon alkanes are very soluble inthe azeotrope-like compositions of this invention, and so theazeotrope-like compositions are excellent solvents for the cleaningprocess of this invention. These compositions will also be effective assolvents for depositing hydrocarbon coatings, e.g., coatings oflubricant, onto substrate surfaces.

                                      TABLE 4                                     __________________________________________________________________________    Ex-              Ether Conc.                                                                         Organic   Hydrocarbon @ RT                                                                       Hydrocarbon @ BP                                                                       Boiling Point                                                                        Pressure                                                                       ample Organic                                                                Solvent:Ether                                                                 (wt %) Solvent                                                                Conc. (wt %) (#                                                               carbon atoms)                                                                 (# carbon                                                                     atoms) (°                                                               C.) (torr)         __________________________________________________________________________    73  Hexane:Ether A                                                                             59.7  40.3      21       24       62.3   725.1                 74 Heptane:Ether A 92.5 7.5 13 18 74.3 728.6                                  75 Heptane:Ether B 89.7 10.3 13 20 73.7 738.9                                 76 Isooctane:Ether A 91.0 9.0 13 19 75.2 728.6                                77 Isooctane:Ether B 90.9 9.1 13 20 74.3 736.1                                78 Cyclohexane:Ether A 66.5 33.5 15 >24 66.9 724.2                            79 Cyclohexane:Ether B 74.5 25.5 14 24-28 66.6 735.4                          80 Methylcyclohexane:Ether A 88.6 11.4 13 19 74.3 738.7                       81 Methylcyclohexane:Ether B 90.6 9.4 13 19 74.5 736.7                        82 t-Amylmethyl Ether: 85.4 14.6 15 21 74.4 738.4                              Ether A                                                                      83 t-Amylmethyl Ether: 85.2 14.8 15 22 74 735.2                                Ether B                                                                      84 Tetrahydrofuran:Ether A 55.4 44.6 21 >24 62.8 731.8                        85 Tetrahydrofuran:Ether B 52.6 47.4 20 28-32 61.9 727.3                      86 Tetrahydropyran:Ether A 83.3 17.7 15 23 72.4 724.8                         87 1,4-Dioxane:Ether A 91.8 8.2 14 19 73.7 725.8                              88 1,2-Dimethoxyethane: 82.2 17.8 16 22 74.3 728.6                             Ether A                                                                      89 1,2-Dimethoxyethane: 81.9 18.1 16 23 73.7 736.8                             Ether B                                                                      90 Ethyl Acetate: Ether A 68.2 31.8 19 >24 70.7 730.6                         91 Ethyl Acetate: Ether B 69.3 30.7 18 24 to 28 70.7 739.0                    92 Methyl Propionate:Ether A 73.0 27.0 18 >24 71.4 732.5                      93 Methyl Ethyl Ketone:Ether 86.2 13.8 15 >17 71.7 732.5                       A                                                                            94 Methyl Ethyl Ketone:Ether 78.9 21.2 17 24 to 28 70.8 734.2                  B                                                                            95 Methanol:Ether B 84.5 15.5 11 14 52.8 730.6                                96 Ethanol:Ether B 88.0 12.0 13 20 65.3 730.9                                 97 2-Propanol:Ether B 87.1 12.9 14 20 65.3 730.9                              98 t-Butanol:Ether B 83.7 16.3 15 22 67.5 733.8                               99 Pentafluoro-1- 75.3 24.7 9 13 67.6 733.8                                    Propanol:Ether B                                                             100 Hexafluoro-2- 34.7 65.3 5 8 56.9 733.6                                     Propanol:Ether B                                                             101 Hexamethyl Disiloxane: 90.6 9.4 13 18 75.7 731.9                           Ether A                                                                      102 Hexamethyl 89.6 10.4 13 20 75.1 738.5                                      Disiloxane:Ether B                                                           103 1-Chlorobutane:Ether A 74.2 25.8 18 >24 69.2 729.8                        104 1-Chlorobutane:Ether B 71.9 28.1 18 24 to 28 68.9 740.3                   105 1,2-Dichloropropane:Ether 83.6 16.4 15 19 73.9 729.6                       A                                                                            106 1,2-Dichloropropane:Ether 86.8 13.2 14 20 72.9 731.9                       B                                                                            107 2,2-Dichloropropane:Ether 54.9 45.1 21 >24 65.7 729.4                      A                                                                            108 2,2-Dichloropropane:Ether 61.7 38.3 19 >28 65.3 739.6                      B                                                                            109 trans-1,2- 37.3 62.7 22 >24 45.7 730.6                                     Dichloroethylene:Ether A                                                     110 trans-1,2- 31.2 68.8 22 >28 45.2 730.5                                     Dichloroethylene:Ether B                                                     111 2,3-Dichloro-1- 81.6 18.4 14 21 73.0 724.6                                 propene:Ether A                                                              112 1-Bromopropane:Ether B 56.0 44.0 19 24 to 28 62.9 730.0                   113 Acetonitrile:Ether A 83.0 17.0 9 14 63.8 726.7                            114 Acetonitrile:Ether B 85.4 14.6 10 16 64.2 740.5                         __________________________________________________________________________

Example 115

The following Example illustrates that azeotrope-like compositions canbe used for dry cleaning fabrics.

A cleaning solution was prepared using an azeotrope-like compositionprepared from 37 weight percent Ether A and 63 weight percenttrans-1,2-dichloroethylene, and 1 volume percent of SECAPUR PERFECT, adry cleaning detergent available from Buesing and Fasch GmbH ofOldenburg, Germany, and 0.1 volume percent water.

15×15 cm swatches of a 70/30 percent polyester/wool blend fabric and a65/35 percent polyester/cotton blend twill fabric were stained byapplying, at three different sites on each fabric swatch, three drops ofcorn oil, three drops of mineral oil and three drops of dirty motor oil.The oil stains were then driven into the fabric swatches by placing a11.2 kg (5 pound) weight over the swatches for 1 minute and the stainswere then allowed to further set for about 1 hour.

After the stains were set, the fabric swatches were cleaned in thecleaning solution by agitating the swatches in about 500 mL of cleaningsolution for about 15 minutes. The swatches were then removed, air driedand evaluated for any remaining stain using a Chromometer™ CR-300 fromMinolta Camera Company of Japan. The ΔE measurements for the cleanedfabrics were only slightly greater than the unstained fabric or about0.0 to 0.32 thus illustrating that the cleaning solution made of theazeotrope-like composition is an effective dry cleaning agent.

Example 116

Ether B can also be made according to the following procedures.Perfluoroisobutyryl fluoride, was prepared by electrochemicallyfluorinating isobutyric anhydride (>99% pure) in a Simons ECF cell ofthe type described in U.S. Pat. No. 2,713,593 (Brice et al. ) and inPreparation, Properties and Industrial Applications of OrganofluorineCompounds, R. E. Banks, ed., John Wiley and sons, New York, 1982, pp. 19to 43 to form a perfluoroisobutyryl fluoride product containingapproximately 56 wt. % perfluoroisobutyryl fluoride, 24 wt. %perfluoro-n-butyryl fluoride and 20 wt. % percent perfluorinated, inertproducts.

A 600 mL stainless steel Parr pressure reactor was charged withspray-dried potassium fluoride (1.10 mole equivalents relative toperfluoroisobutyryl fluoride), anhydrous diglyme (1.0 weight equivalentrelative to perfluoroisobutyryl fluoride), Adogen™464 (0.0065 moleequivalents relative to perfluoroisobutyryl fluoride, purified bydissolving in diglyme, followed by fractional distillation to removeisopropanol) and tribenzylamine (0.03 mole equivalents relative toperfluoroisobutyrl fluoride). The vessel was sealed, cooled with dryice, charged with perfluoroisobutyryl fluoride then allowed to warm toroom temperature with stirring. Diethyl sulfate (1.30 mole equivalentsrelative to perfluoroisobutyryl fluoride) was then charged to thereactor under pressure and the reactor held at 25° C. for 30 minutes,heated to 40° C. for an additional two hours, then heated at 60° C. foran additional 18 hours.

The reactor was then charged with aqueous potassium hydroxide (60g of 45wt % and 50 g water) to neutralize any unreacted diethyl sulfate andstirred for 30 minutes at 85° C. until the solution pH was greater than13. Excess aqueous hydrogen fluoride (48 wt % concentration) was addedto the solution until the pH was 7-8, and the product 1-ethoxynonafluoroisobutane fraction was distilled from the reaction mixture.The distillate was washed with water to remove small amounts of ethanol,then fractionally distilled to further purify the desired product.

Various modifications and alterations of this invention will be apparentto those skilled in the art without departing from the scope and spiritof this invention.

We claim:
 1. An azeotrope-like composition including (a) perfluorobutyl ethyl ether which ether consists essentially of perfluoro-n-butyl ethyl ether and perfluoroisobutyl ethyl ether and (b) organic solvent, the azeotrope-like composition being selected from the group consisting of:(i) compositions consisting essentially of about 94 to 35 weight percent of the ether and about 6 to 65 weight percent methanol that boil at about 52 to 54° C. at 720 torr; (ii) compositions consisting essentially of about 94 to 55 weight percent of the ether and about 6 to 45 weight percent ethanol that boil at about 61 to 63° C. at 722 torr.
 2. An azeotrope-like composition including: (a) perfluorobutyl methyl ether, wherein said ether consists essentially of about 18 weight percent perfluoro-n-butyl ethyl ether, and about 82 weight percent perfluoroisobutyl ethyl ether, and (b) organic solvent, that is selected from the group consisting of:(i) compositions consisting essentially of the ether and methanol, wherein the compositions, when fractionally distilled, form a distillate fraction that is an azeotrope consisting essentially of about 84 weight percent of the ether and 16 percent of the methanol that boils at about 53° C. at about 731 torr; (ii) compositions consisting essentially of the ether and ethanol, wherein the compositions, when fractionally distilled, form a distillate fraction that is an azeotrope consisting essentially of about 88 weight percent of the ether and about 12 percent of the ethanol that boils at about 62° C. at about 731 torr; (iii) compositions consisting essentially of the ether and 2-propanol, wherein the compositions, when fractionally distilled, form a distillate fraction that is an azeotrope consisting essentially of about 87 weight percent of the ether and about 13 percent of the 2-propanol that boils at about 65° C. at about 731 torr; (iv) compositions consisting essentially of the ether and t-butanol, wherein the compositions, when fractionally distilled, form a distillate fraction that is an azeotrope consisting essentially of about 84 weight percent of the ether and about 16 percent of the t-butanol that boils at about 67° C. at about 741 torr; wherein the concentrations of the ether and the organic solvent in the azeotrope-like composition differ from the concentrations of such components in the corresponding azeotrope by no more than ten percent.
 3. An azeotrope-like composition according to claim 2 wherein the concentrations of the ether and the organic solvent in the azeotrope-like composition differ from the concentrations of such components in the corresponding azeotrope by no more than five percent.
 4. An azeotrope-like composition according to claim 3 wherein the azeotrope-like composition is an azeotrope. 